1. Field of Invention
The invention relates to an appliance for distributing and placing I-shaped surgical fasteners which may, for example, be used for fixing parietal and visceral reinforcements.
It is aimed more especially at replacing permanent metal fasteners and staples with fasteners made of plastic, for example, of resorbable material, having a temporary function consistent with the reinforcing tissue recovery time, while at the same time affording anchorage excluding the risks of trapping nerves.
2. Description of Related Art
Already known from the textile industry is a plastic fastener in the overall shape of an I, that is to say made up of a head, of a connecting filament and of a foot. This fastener is distributed and placed by means of an appliance in the form of a gun the barrel of which is extended by a hollow needle and the body of which is fitted with a manual actuating control. To connect various elements in sheet form, for example for connecting a label to a garment, the needle is engaged transversely through these elements, by pushing it in by hand, then actuation of the manual control, through the displacement of a plunger arranged along the longitudinal axis of the canal of the needle, causes:
a fastener forming part of a strip of fasteners in attendance in a magazine to be selected,
the head of the fastener to be moved into the axial canal of the hollow needle,
the head of the fastener travelling along the needle to pass through the sheets,
and then, as soon as the connecting filament comes into contact with the sheets, it to be folded down against the head and engage through the sheets with the remainder of the head until the head lies completely on the other side of the sheets that are to be held together.
At the end of actuation, a means, for example a spring, returns the plunger and the needle is withdrawn by hand. Under the action of the elasticity of the material of which the fastener is made, the head thereof returns to its initial position and once again becomes more or less perpendicular to the connecting filament, anchoring the fastener on the rear face of the sheets. These are then trapped between the head and the foot of the fastener which also runs transversely, but on the front side of the sheets.
It has been imagined for this type of fastener to be carried over into surgical ligatures, for example for binding a textile reinforcement against biological tissues, by making the fastener out of plastic and, in particular, out of a bioabsorbable material and by distributing it using an equivalent distributor. Disadvantages have then arisen and these stem from the bulk generated by the strip of fasteners projecting from the tip of the distributor, and from those inherent in meeting surgical specifications, particularly those relating to sterilization. This is the case of the appliances described in U.S. Pat. No. 4,448,194 and WO98/51179.
To overcome these disadvantages, document WO00/67644 describes a distribution and placement appliance comprising a handgrip body quipped with first and second controls and with an end-piece, and an elongate element, attached and fixed to the end-piece, in which appliance the elongate element is made up of a body of tubular overall shape containing:
near its free end, a magazine slide itself containing couched I-shaped fasteners each having an anchoring bar, a catching bar and a connecting strip, the said slide being, on the one hand, movable in the elongate element by a longitudinal rod which can be actuated by the first controls on the handgrip and, on the other hand, secured to a split and longitudinal hollow needle projecting from its free end and able to project from this elongate element,
and, in its tubular body, on the one hand, means for distributing the stored fasteners one by one, this distribution involving the transferring of the anchoring bar of the first fastener into an accommodating housing arranged in the continuation of the hollow needle and, on the other hand, an ejection plunger which can be moved by the second controls on the handgrip and which is arranged in line with the hollow needle so as to push the anchoring bar of the awaiting first fastener thereinto.
In this appliance, the fasteners are, in their storage magazine, subjected to the constant force of a pushing blade which urges them towards the free end of the appliance and which, in conjunction with a sloping ramp, tends to drive the anchoring bar of the first fastener into an accommodating housing formed behind the split needle, but closed off at rest by the plunger. Actuation of the controls on the handgrip first of all causes the slide to move so that the needle projects from the free end of the elongate element, this movement taking place with no movement of the plunger, so as to form the accommodating housing which then accommodates the anchoring bar of the first fastener.
Secondly, the plunger is moved by the second controls so as to drive the anchoring bar of the fastener into the needle, then from the needle into the biological tissues that are to take it. At the end of distribution, the catching bar of the fastener in the process of being placed passes against an inclined ramp belonging to the slide and which is supposed to cause it to pivot so that it does not come into abutment against the tissues but lies against them.
It has been found in practice that this ramp is not enough to cause the catching bar to pivot satisfactorily, which means that it can still butt against the reinforcement, impeding distribution and the righting movement that the anchoring bar needs to effect in the biological tissues.
It should be pointed out here that, unlike fasteners used for connecting textile components, in which the anchoring bar rights itself behind the sheets, but in the atmosphere, in order through the elasticity of the material of which it is made to adopt a position parallel to the sheets, the anchoring bar of a surgical fastener has to right itself in the biological tissues, that is to say against the resistance thereof. This righting entails a force that exceeds the elastic capabilities of the material and is not well catered for in the appliances of the prior art, which means that the positioning of the anchoring bar and the anchoring of the fastener in the biological tissues are haphazard.
These disadvantages are exacerbated with fasteners made of a material which has low elasticity or nervosity, as is the case of bioabsorbable materials because as the fastener is distributed into the tissues, the mechanical properties of the material reduce the elastic righting ability of its anchoring and catching bars, and this leads to poor anchorage in the tissues.
Finally, with fasteners made of bioabsorbable material or material with low elasticity, the constant pressure on them from the spring means pushing them towards the exit from the magazine tends to deform them in creep. This generates distribution problems leading to the scrapping of the appliance.
It is an object of the present invention to provide an appliance for storing, distributing and placing surgical fasteners which reduces the stresses exerted on the fasteners in attendance in the magazine and which makes them easier to place by organizing the movements that distribute them.
This appliance reuses the essential elements of the one described in document WO00/67644 described hereinabove, but reconfigures them.
To this end, the accommodating housing of the magazine slide contains, at rest, the anchoring bar of the first fastener awaiting placement, of which fastener the catching bar, arranged at the end of the magazine, is free of any thrusting force, while this magazine slide comprises:
below the needle and in the path via which the said catching bar leaves the magazine, a transverse finger able, as the fastener is distributed by movement of its anchoring bar by means of the plunger, to have the downstream end of this catching bar bear against it to force it to pivot by raising its upstream end,
beside the needle, a downwardly projecting rib able to guide the pivoting and movement of the upstream end of the catching bar so that the latter does not butt against the needle,
and, on the transverse finger, a sloping face driving the downstream end of the catching bar transversely away from this finger.
Thus, when the appliance is at rest, the first fastener and the next ones are not subjected to any thrusting force, including the first fastener the anchoring bar of which is already in place in the accommodating housing of the magazine slide. By virtue of this, the stored fasteners are kept in their original condition and are therefore not at risk from creep, even in the case of weakly elastic materials.
When the fastener is distributed, the finger, the rib and the slopes of the slide, which in turn collaborate with the catching bar, first of all allow the movement imparted by the plunger to the anchoring bar to be used to cause the catching bar to pivot and to orientate it roughly parallel to the reinforcement and then allow the catching bar to be used to retain the anchoring bar and force it to pivot in the biological tissues so that it adopts a position parallel to this textile reinforcement.
Thus, at the end of placement and without excessive stresses having been exerted on the fastener, the fastener is always perfectly positioned and therefore provides perfect anchoring.
In one embodiment of the invention, the catching bar of the first fastener is, in the magazine, in contact with the catching bars of the other fasteners stored, and the catching bar of the last fastener is in contact, but without significant force, with the end of a buffer rod which can be moved step by step, this buffer rod being connected to means able, at the end of the movement of distributing the first fastener into the tissues, and through movement of the second controls on the handgrip, to move it by the length of the catching bar of one fastener so that, as the magazine slide returns to its starting and rest position in the tubular body, contact between the end of this buffer rod and the catching bar of the last fastener causes the row of fasteners to move within the magazine, and causes the anchoring bar of the first fastener to be transferred into the accommodating housing.
Thus, once the first fastener has been distributed, the accommodating housing is reloaded automatically, as the slide returns into the body, by abutment of the catching bar of the last fastener against the buffer rod, which is moved forward by just one step corresponding to the length of the catching bar of a fastener.
Advantageously, the magazine slide is formed of two plastic shells joined together along their median, longitudinal and vertical plane, the shell secured to the hollow and split needle having two longitudinal slots arranged near its edges and able, one of them, to receive the catching bars of the fasteners and the other the anchoring bars, the slot for the catching bars opening freely at the front end of the slide while the slot for the anchoring bars continues in an inclined plane for guidance in the direction of the needle, while the other shell has a longitudinal channel coaxial with the needle for the ejection plunger and, in the accommodating housing of the needle, a vertically inclined resting plane for the connecting strip of a fastener.